The present application relates generally to gas turbine combustion technology and, more specifically, to a fuel injection micro-mixer nozzle arrangement for a turbomachine combustor.
Combustion instability/dynamics is a phenomenon in turbomachines, especially those utilize lean pre-mixed combustion system. Low frequency combustion dynamics is typically excited as axial modes, whereas high frequency dynamics as radial, azimuthal and axial modes by the combustion process commonly referred to as “screech”. Combustion dynamics can affect all combustor components, even the parts upstream and downstream. Under certain operating conditions, the combustion component and the acoustic component couple to create a very high pressure fluctuation inside the combustors that has a negative impact on various turbomachine components with a potential for hardware damage. More specifically, fluctuations in the fuel-air ratio are known to cause combustion dynamics that lead to combustion instability. Creating perturbations in the fuel-air mixture by changing fuel flow rate can disengage the combustion field from the acoustic field to suppress combustion instability.
Further, the combustor may be affected by non-uniform temperature profile and non-uniform mixing of fuel and air across the combustor region, thereby, negatively impacting the performance and efficiency of the turbomachine combustor.
There is therefore a desire for a system and method that improves air uniformity of micro-mixer nozzles and reduce amplitudes of combustion dynamics in the combustor which would be useful to enhancing the thermodynamic efficiency of the combustor, protecting the combustor from catastrophic damage, and/or reducing undesirable emissions over a wide range of combustor operating levels.